Default name change request: published_date_YYYYMMDD - channel_name - title.format

I recommend the default video name be changed from:

`output = '{videoDetails.title}';`

title.format

to:

`output = '{videoDetails.publishDate} - {videoDetails.author.name} - {videoDetails.title}';`

published_date_YYYYMMDD - channel_name - title.format

This way all the major video meta data is in the filename. It'll help with directory ordering, as well as not over writing videos unintentionally, and it'll help with finding downloaded content. Besides, it's always easier removing unwanted data from a name, than adding it back in. This way you could simply issue "ytdl " and it would work well in 99% of situations without added flags.